TABLE 5

Metabolic stability of PDE9 inhibitors in human liver microsomes

Compound	k	T_1/2	CL_int	CL_app	CL_h	E_h
		minute	ml/min/mg	ml/min/mg	ml/min/mg	%
Testosterone	0.035	20.0	0.069	66.9	15.4	78.0
	0.165	4.2	0.329	1296	84.2	93.5
Warfarin	−0.001	Stable	Stable	Stable	Stable
	−0.003	Stable	Stable	Stable	Stable
(S)-C33	0.007	105	0.013	12.7	7.8	38.9
	0.013	53.5	0.026	102	47.8	53.1
(R)-C33	0.016	44.0	0.032	30.4	12.1	60.3
	0.034	20.2	0.069	270	67.5	75.0
Racemic C33	0.013	51.4	0.027	26.0	11.3	56.5
	0.022	31.3	0.044	174	59.4	66.0
C40	0.011	62.2	0.022	21.5	10.4	51.8
	0.002	291	0.008	19	15.5	17.2
3r^a	0.058	11.9	0.116	112	17.0	84.8
	0.031	22.3	0.062	244	65.8	73.1